Calendar not sending invitation emails when creating event with third party app

Nextcloud version: 26.0.5
PHP version: 8.2
Calendar App Version: 4.5.2

The issue you are facing:
Calendar invitations are not sent when I invite someone using my phone. When inviting using the webinterface, the other person gets an email where they can accept/decline.
When I invite someone on my phone, the webinterface shows that this person got an invitation (invitation sent), but no email was sent

Steps to replicate it:

  1. Sync nextcloud calendar to phone (e.g. with DavX)
  2. Create new Event on phone and add email to invited field
  3. no email is sent

Since I am using my phone quite often to create events, it is no option to always log in to the webinterface to create events

Is there any way that events are also sent if I use my phone and sync the events? (In my case the google calendar app)

Please have a look on this discussion which might help you to solve the issue: